The invention relates to a heat exchanger for the independent heating of the driver and front-seat passenger sides of a motor vehicle. The heat exchanger has two ribbed pipe blocks which are separated from one another but are assigned to a common upper and lower water compartment. A heating medium, in particular engine cooling water and air, flows through each of the ribbed pipe blocks. The ribbed pipe blocks each comprise several parallel pipes and ribs at right angles to the pipes, having flow and return connections which are positioned at a longitudinal side of the upper water compartment. The two return connections of the ribbed pipe blocks are located on either side of a central flow connection. Each return connection is connected to a collecting chamber which is positioned at the lower portion of the upper water compartment.
One problem with the known art is that the best exchanger is designed in such a way that the flow is guided centrally through the ribbed pipe blocks and then returned through pipes positioned on the outermost ends of the ribbed pipe blocks. This can result in disadvantages in the thermal stratification, in particular when using a heat exchanger of this type for automatically controlled heating or air-conditioning installations.
It is an object of the invention to alleviate this disadvantage while retaining the construction of essential parts of the heat exchanger, in particular the ribbed pipe blocks.
This objective is achieved according to the invention in that pipes located in the area of the ends of the heat exchanger are provided as flow pipes, and that the flow connection is connected to the flow pipes via a transverse channel which is located above the collecting chamber into which the return pipes open.
By means of this arrangement, it is possible to operate a heat exchanger of the type mentioned above such that the flow is guided around the outermost ends of the heat exchanger, that is, to the right and left ends with respect to an upright heat exchanger, whereas the return flow is guided centrally through the intermediate area. In this way, the desired stratification for automatic operation is obtained, and can be effected without further substantial interference with the construction of the heat exchanger. Thus, at least with respect to the ribbed pipe blocks, heat exchangers of the same construction can be used for both the central guidance of flow (with return flow on the outermost ends of the heat exchanger) and the guidance of flow on the outermost ends of the heat exchanger (with a central return flow).
In preferred embodiments of the invention, the transverse channel is adjacent to a longitudinal side of the upper water compartment, which longitudinal side is opposite the longitudinal side having the central and return flow connections.
Moreover, a constructionally simple design is provided if the transverse channel is made as a channel which is open to at least one of the narrow sides of the heat exchanger and can be closed by an insert. Thus, the water compartment can also be advantageously made as a casting.
A further advantageous feature of the invention for a water compartment for a heat exchanger having a laterally outward directed flow is that the transverse channel, together with the flow connection, is formed by two shell halves. One shell half is formed into the upper side of the water compartment and the other shell halve is placed onto the upper side of the water compartment. Such an embodiment can be efficiently produced and has the further advantage of having good connection possibilities. In particular, good connections occur when the dividing plane of the two shell halves coincides with the center plane through the flow and return connections.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.